What an operator will and will not combine into one market
Not every set of outcomes is allowed to become one market. Some combinations are permitted and priced automatically, some are permitted only with a person pricing them, and some are refused because the legs cannot all happen, or cannot be settled on one rule, or because the model has nothing to say about them.
- rules read
- 40
- permitted
- 22
- manual price
- 11
- refused
- 7
An operator combines only what it has a rule for. Of 40 documented rules in sample C, 22 permit a combination outright, 11 require a person to price it manually and 7 refuse it. The refusals divide into legs that cannot all happen, legs that cannot be settled on one rule, and combinations the model cannot price.
The three families of rule
The first family is mutual exclusivity. Two outcomes in the same market cannot both happen - a team cannot win and draw - so a combination that needs both is not a market but a contradiction. The second is a settlement dependency: a 90-minute result and a match to be decided in extra time are settled on different rules, and a single combination that needs both cannot be settled at all unless one rule is chosen and stated. The third is coverage: the model has chances for the legs it can see, and nothing for the ones it cannot, which is where most of the 131 requests in sample B were lost.
Legs that merely look risky are not excluded. A 50.00 outsider can be combined with anything the model covers, because the price absorbs the risk. What cannot be combined is a set of outcomes that is not internally consistent, and that is a much smaller list than readers assume - seven of forty rules, on the samples.
What the samples show
| Treatment | Rules | Share | Example |
|---|---|---|---|
| Permitted, priced automatically | 22 | 55.0% | Match result with a goals market |
| Permitted, priced by hand | 11 | 27.5% | A long combination above the model's normal range |
| Refused outright | 7 | 17.5% | Opposing outcomes in one market |
| Every documented rule | 40 | 100% | Legs: minimum 2, maximum 12 |
What the rules do not say
Almost nothing in the sample corpus explains why a permitted combination is permitted. The rules state the treatment and not the reason, and the reason is usually the model rather than the market: a combination is automatic when the operator has a correlation estimate for every pair inside it, and manual when it does not. That is the link between this page and /the-model: the rulebook is the model's own coverage, written down as a list of permits.
- Whether the minimum and maximum leg counts are stated where the market is composed, not only in the general terms.
- Whether the page explains that some combinations are priced by hand rather than automatically - 11 of the 40 rules do.
- Whether anything states what happens when two legs become mutually exclusive by a later event, such as a withdrawn player.
- Whether the settlement rule of each leg is stated, and which rule wins if two legs of one combination would be settled differently.
- Whether the rules say that a priced combination may still be refused, which is the subject of /the-refusals.